DE29807638U1 - Embossing foil with individually identified security features - Google Patents

Description

B/34.764/AM/ts

Leonhard Kurz GmbH'S Co. Schwabacher Strasse 482. 90763 Fürth

Embossing foil with individually marked security features

The present invention relates generally to the marking of security features on stamping foils, in particular to a device for carrying out the method and to a stamping foil with correspondingly marked security features.

Embossed holograms and other security features, such as partially demetallized foils, are increasingly being used for banknotes, check cards, etc. These security features are usually provided on a hot stamping foil and transferred by hot stamping. When producing the hot stamping foil, fine reliefs are introduced into the surface using an embossing die or the metallization is partially removed. The individual security features are created on a foil roll, from which they are individually removed during transfer. A foil roll always represents a batch in which the security features are completely identical. Individualization has not yet been carried out. For various reasons, such as security reasons and better identifiability and also for billing, individual marking of each individual security feature, in particular a consecutive numbering, is necessary.

desirable. Such marking represents an additional security feature that is difficult to counterfeit.

DE 41 34 271 Cl discloses a method for decorating or labeling a surface using a laser beam, in which at least the upper or first colored lacquer layer to be removed using a laser beam is applied to the surface using a transfer process in order to achieve a uniform thickness of this colored lacquer layer and thus a very uniform engraving. However, the subject of this publication is a decoration and not a security feature.

EP 0 383 956 A1 discloses a method and a device for producing images or characters on a substrate which is provided with a layer of color arranged on the substrate that absorbs a laser beam and a further layer of color arranged on this, the latter being removed by the laser beam. The control of the laser beam for producing the security marking is basically carried out in dependence on a reading zone that is also located on the substrate.

Commercially available CO2/Nd:YAG and excimer lasers are generally used for laser beam marking. In the area of interaction between the laser beam and the workpiece, material is liquefied, decomposed, vaporized or removed. Short laser pulses are particularly suitable for processing thin layers. Common marking methods used for this are mask projection, in which a mask is transferred to the object in the beam path, usually in a reduced size, and the scanning method, in which a focused laser beam creates the marking using relative movement. However, these methods are not particularly suitable due to their lack of flexibility or their high speed.

Due to their low speed, they are little to not at all suitable for marking security features in the production process when manufacturing stamping foils.

Electron radiation can also be used for marking, whereby this leads to heating, evaporation or plasma formation in metallic materials depending on the power density. This can be used in particular to mark metallized hot stamping foils.

Another option is to mark using a thermal transfer process. The marking is created by the action of a thermal transfer print head on a thermal transfer foil that is in contact with the foil to be marked.

Finally, inkjet processes can also be used, in which ink is transferred to the film using an inkjet nozzle.

It is an object of the present invention to provide a stamping foil with improved safety properties and a device for producing such a stamping foil.

This object is achieved by an embossing foil according to claim 1 and a device for producing such an embossing foil according to claim 13. Special embodiments of the invention are the subject of the respective subclaims.

The stamping foil according to the invention has for the first time at least one security element which is/are provided with an individualizing marking. It is particularly advantageous

that this individualizing identification of the individual
Security features are spatially and temporally in close proximity to the production of the respective security feature, because this enables a precise recording of the manufactured
Security features without compromising

production speed. Since the individualizing
Marking of the security features represents a further, additional security feature and this feature, as previously
mentioned, spatially and temporally close to the production of the
respective security feature, i.e. in particular since the individualizing marking is produced in the same device as the security feature itself, the possibility of manipulation is practically
excluded. This would not be the case if the

Security features would first be created on an embossing foil and the individualising marking of the security features would take place at a different time and possibly also at a different place and in a different device.

A further advantage is that the marking takes place immediately after the security feature has been created, because
further production steps in which further
layers are applied and the marking is therefore inside the hot stamping foils and thus protected from damage,
protected against aging and counterfeiting.

Preferably, the individualizing marking is carried out by means of a digital code, in particular a dual or bar code. In a particularly preferred embodiment of the
In the method according to the invention, at least part of the
Labelling continuous, in particular a continuous
Numbering or a consecutive letter and/or
This removes all the benefits for

Transferable security features are available on embossed foils that can be accessed via a serial number, as is the case with banknotes, for example. In particular, the path of each individual security feature can be precisely tracked, making misuse of the security feature marked in this way more difficult, if not impossible.

Advantageously, the individualized marking is carried out using a laser or an electron beam source, i.e. the radiation energy is generated using a laser or an electron beam source, as these can be easily focused and therefore enable high processing precision and/or very small markings.

They also enable high writing speeds, which are necessary for marking security features without affecting production, i.e. in particular the production speed, since laser and electron beam sources can be modulated with high frequencies up to the MHz range.

The prerequisite for marking using a blasting process is sufficient absorption of the radiation in at least one layer of paint or, if present, the reflective layer.

One embodiment therefore provides for the marking to be carried out by removing at least one layer of paint and/or the reflective layer, if present. The marking becomes visible due to the changed reflection or transmission or changed brightness or color.

A further embodiment provides for the marking to be carried out by a change, in particular a smoothing of the relief structure contained in the security feature. The absorbed

Radiation energy leads to relief destruction or leveling of the heated area due to the viscoelastic material behavior. The changed reflection behavior makes the marking visible.

A further embodiment provides for the marking to be carried out by changing a color layer that is sensitive to the wavelength. This change generally consists of a discoloration, whereby particular mention should be made of the possibilities that the sensitive color layer becomes colorless or shows a color change or generally becomes opaque.

In a further special embodiment of the method according to the invention, a diode laser is used to generate the radiation energy. This offers the advantage that the equipment required is kept comparatively low and, if necessary, the number and arrangement of the radiation sources can easily be changed if the width of the film web or the width or, in general, the size or number of the security features to be marked changes. For example, a diode laser with a wavelength of 808 nm can be used to produce a marking with a diameter of approx. 200 nm. With a pulse duration of 100 με, an energy density of 5 to 10 J/cm is required.

Another special design involves using Nd:YAG or fiber lasers to generate the radiation energy. Due to their good beam quality, these lasers can be focused very well and are therefore particularly suitable for generating very small markings.

In a further embodiment, the marking is done by thermal transfer printing or inkjet printing.

layers of varnish or ink particles are transferred locally onto the film.

It is further particularly preferred if the individualizing marking of the security features of the stamping foil is carried out in a time-dependent manner depending on the transport speed of the stamping foil.

In another embodiment of the method according to the invention, the individualizing marking is carried out in indirect dependence on the transport speed of the stamping foil. The presence of a security feature on the stamping foil is determined using an optical sensor and the signal that can be taken from the optical sensor when a security feature is present is used to control the generation of the individualizing marking. The fact that this is an indirect dependence on the transport speed of the stamping foil means nothing other than that the transport speed of the stamping foil is not measured, but that the individualizing marking is carried out when the optical sensor determines the presence of a security feature. Of course, this also depends on the transport speed of the stamping foil, although this can be omitted.

It is fundamentally possible to provide the individualizing marking of the security features on the security feature itself or outside the security feature. In this case, it does not require any explanation for the person skilled in the art that, for example, an individualizing marking of a security feature formed from a diffractively effective, spatial structure can be achieved by partially smoothing the diffractively effective, spatial structure.

structure can only be created after the security feature has been created.

The individualizing marking of each security feature can in principle be carried out in any orientation. It is particularly preferred if the individualizing marking is carried out essentially parallel to the running direction of the embossing foil, as this keeps the necessary equipment expenditure to a minimum, in particular a deflection device for deflecting the beam that generates the individualizing marking can be dispensed with. This arrangement is also particularly suitable for marking using thermal transfer printing or inkjet.

In another embodiment of the method according to the invention, the marking is produced essentially at a right angle to the running direction of the stamping foil. In this case, just as when producing the individualizing marking with a different orientation, it is necessary for the device for carrying out the method to have a corresponding deflection device. When using a diode, Nd:YAG or fiber laser to produce the individualizing marking, the deflection device is preferably formed by a polygon mirror and particularly preferably by a galvanometer mirror. If the individualizing marking is produced by means of an electron beam, the deflection device is formed by a magnetically acting unit, such as an arrangement of one or more electromagnets.

In addition to the individual marking, individual or multiple security features can be provided with additional information. Additional information can include, in particular, details about the manufacturer, the

Date of manufacture and/or place of manufacture. It is particularly advantageous that this information can be changed with very little effort via the control of the radiation source or the print head, which is particularly advantageous when marking with the date of manufacture or other information that may change frequently.

The present invention is described in more detail below using embodiments and with reference to the attached figures. They show:

Figure 1 is a schematic representation of the marking according to the invention using radiation energy parallel to the transport direction of the stamping foils;

Figure 2 shows a schematic representation of the marking according to the invention using radiant energy in the form of a bar code;

Figure 3 is a schematic representation of the principle of individualizing marking that takes place transversely to the transport direction of the stamping foil;

Figure 4 is a schematic representation of the marking according to the invention using radiation energy by removing layers of paint;

Figure 5 shows a schematic representation of the marking according to the invention by means of radiation energy by changing, in particular smoothing, a relief structure;

Figure 6 shows a schematic representation of the marking according to the invention by means of radiation energy by removing a lacquer layer before embossing an optically effective, spatial structure;

Figure 7 is a schematic representation of the marking according to the invention using radiant energy by changing a color layer sensitive to the wavelength;

Figure 8 shows a schematic representation of the marking according to the invention using a thermal transfer process;

Figure 9 is a schematic representation of the inventive marking by means of inkjet printing;

Figure 10 is a schematic representation of the elements for

Control of the radiation source for generating the marking according to the invention by means of an optical sensor;

Figure 11 is a schematic representation of a

stamping foil according to the invention, from which it can be seen that the individualizing marking can be arranged inside and outside the area of the security feature.

Figure 12 is a schematic representation with a field for the marking according to the invention provided in accordance with the feed direction of the film and a field at right angles to the feed direction of the film;

Figure 13 is a schematic representation of the parallel arrangement of several writing heads when generating an individualizing marking of a security feature; and

Figure 14 is a schematic representation of a detection of the individualizing marking of security features arranged sequentially on a film by means of a corresponding reading head.

Figure 1 shows a schematic representation in which an embossing foil 1 is provided with an individualizing marking 3 by a laser beam 2 parallel to the running direction indicated by the arrow.

Figure 2 shows a corresponding marking 3, where instead of a binary code, an individualizing marking is represented by a bar code.

Figure 3 shows a schematic representation of the principle of individualizing marking that takes place transversely to the transport direction of the stamping foil, whereby the arrows in the figure indicate the transport direction of the stamping foil 1 and the marking direction. The marking takes place in the marking fields 4 in such a way that the beam used for marking is deflected via a schematically shown deflection unit 5 while compensating for the feed of the stamping foil. The deflection unit 5 is rotated by the angle f against the transverse direction in accordance with the feed speed.

Figure 4 shows a schematic representation of the inventive marking using radiation energy by removing

Lacquer layers, whereby a laser beam 2 removes a lacquer and, if applicable, separating layer structure 6, so that after exposure the lacquer layers are removed and leave a corresponding gap 7. The lacquer layers can have a relief structure or at least contain a reflective layer in some areas.

Figure 5 shows a corresponding marking by changing a relief structure. A layer structure 6 corresponding to Figure 4, which is provided with a relief structure 8, is irradiated with radiation energy so that the relief structure is destroyed or, in particular, smoothed at the point where the radiation energy hits.

A modification of this principle is shown in Figure 6, whereby the marking is carried out by marking a lacquer layer 10 of the corresponding layer structure 6 by radiation energy, so that the lacquer layer 10 is removed at the point where the radiation energy hits it and subsequently a relief structure 12 is embossed into the lacquer layer 10.

In Figure 7, the marking by means of radiation energy is shown by changing a color layer sensitive to the wavelength, whereby the radiation energy penetrates into a layer structure 6, which can contain a relief structure or at least a reflection layer in some areas, and strikes a sensitive color layer, which changes accordingly at the point of impact 13 of the radiation energy. This change generally consists of a discoloration, whereby the possibilities of the sensitive color layer becoming colorless or showing a color change or becoming opaque are particularly noteworthy.

Figure 8 shows schematically the marking of a transfer film structure, generally designated 14, in a thermal transfer process. In this process, the individualizing marking 3 is transferred by a thermal print head from a thermal transfer film 16 to the substrate, i.e. the transfer layer structure 14 with the security feature to be marked.

Figure 9 shows schematically the marking of a corresponding transfer layer structure 14 with an individualizing marking 3 in an inkjet process. The print head 17 works in this process according to the same principle as is known from conventional inkjet printers.

Figure 10 is a schematic representation of the elements for controlling the radiation source or the print head for producing the marking according to the invention. It is important that an optical sensor 18 detects the presence of a security feature on the stamping foil 1 and forwards this to a control unit 20. The control unit 20 in turn sends corresponding commands to the control unit of the radiation source or the print head 15 or 17, which serves to control the radiation source or the print head 15 or 17, whereby a corresponding individualizing marking is produced in the marking field 4.

Figure 11 shows two possible variants of marking an embossed foil 1 provided with a security feature 19. In one variant, the marking field 4 is arranged within the area of the security feature 19 and in another variant, the marking field 4' is located outside the area of the security feature 19. Of course, it is also possible to use both types of arrangement.

of the marking fields at the same time, so that, for example, additional information can be arranged on the stamping foil 1.

Figure 12 shows schematically the arrangement of the identification field 4 within a security feature 19, whereby it can be seen that the identification field 4 can correspond both to the transport direction of the stamping foil 1 marked with the arrow and can also be arranged at right angles to it.

Figure 13 shows schematically the parallel arrangement of several print heads or radiation sources in this exemplary embodiment when marking security features 19 arranged next to one another on an embossing foil 1. The feed direction of the embossing foil 1 is again marked with an arrow. For reasons of clarity, the part of the device with which the security features are generated is not shown in this figure.

Figure 14 shows a schematic of an arrangement for monitoring or generally for detecting security features 19 based on their individualizing marking 3 by detecting the information contained in the individualizing marking 3 with an optical sensor 23, which can serve other purposes than the optical sensor 18 from Figure 10 and can be formed, for example, by a laser scanner or a CCD camera. In this figure, the transport direction of the embossing foil 1 is again marked with an arrow and the further processing, i.e. the application of the security features provided with an individualizing marking, e.g. on banknotes, credit cards, etc., can for example take place in the schematically shown station 22.

Claims (17)

>' B/34.7 64/AM/ts Leonhard Kurz GmbH & Co, Schwabacher Strasse 482, 90763 Ftirth Sc hut &zgr; a &eegr; s &rgr; r ü c he 1. Embossing foil with one or more security features, characterized in that the embossing foil (1) has an individualizing marking (3) in the form of a marking by means of radiation energy, thermal transfer or ink jet. 2. Embossing foil according to claim 1, characterized in that the individualizing marking (3) consists of a digital code, in particular a dual code or a bar code. 3. Embossing foil according to claim 1 or 2, characterized in that the individualizing marking (3) is continuous, in particular a continuous numbering or a continuous sequence of letters and/or characters. 4. Embossing foil according to one of claims 1 to 3, characterized in that the individualizing marking (3) is arranged within the layer structure (6) of the embossing foil (1). 5. Embossing foil according to one of claims 1 to 4, characterized in that the individualizing marking (3) is arranged on the security feature (19). 6. Embossing foil according to one of claims 1 to 4, characterized in that the individualizing marking (3) is arranged outside the area of the security feature (19). 7. Embossing foil according to one of the preceding claims, characterized in that the individualizing marking (3) is arranged substantially parallel to the longitudinal direction of the embossing foil (1). 8· Embossing foil according to one of claims 1 to 6, characterized in that the individualizing marking (3) is arranged essentially at a right angle to the longitudinal direction of the embossing foil (1). 9. Embossing foil according to one of the preceding claims, characterized in that in addition to the individualizing marking (3) additional information is arranged on the embossing foil (1). 10. Embossing foil according to claim 9,
characterized in that the additional information consists of details about the manufacturer, the date of manufacture and/or the place of manufacture. 11. Embossing foil according to one of the preceding claims, characterized in that the at least one security feature (19) is formed by an embossed hologram or another optically effective, spatial structure. 12. Embossing foil according to one of claims 1 to 10, characterized in that the at least one security feature (19) is formed by a reflective layer present at least in some areas. 13. Device for producing an embossing foil according to one of the preceding claims with a device for producing a security feature, characterized in that a radiation source or a print head for producing the individualizing marking (3) is arranged immediately before or after a device for producing a security feature (19) on an embossing foil (1). 14. Device according to claim (13), characterized in that several radiation sources or print heads are arranged transversely to the running direction of the embossing foil (1). 15. Device according to claim 13 or 14, characterized in that a deflection device (5) for deflecting a beam is arranged between the radiation source and the embossing foil (1). ■ · · ♦· 18 16. Device according to one of claims 13 to 15, characterized in that the radiation source is a diode laser, NrYAG or fiber laser. 17. Device according to claim 16, characterized in that the deflection device (5) is a polygon mirror or a galvanometer mirror.